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Research
Interests
Dr. Todd Silverstein has research
interests in bioenergetics, signal transduction, and enzyme
regulation. Recently many of his student projects have focused
on molecular toxicology, that is, identifying specific protein
activities that underlie cellular pathologies. Special attention
is given to probing the thermodynamics and kinetics of the
toxin-protein interactions. One ongoing project involves characterizing
dose-response curves for heavy metal inhibition of enzyme
activity. Students assay how common hydrolases (e.g., chymotrypsin,
acetylcholinesterase) and redox enzymes (e.g. alcohol dehydrogenase,
lactate dehydrogenase) are inhibited by the toxic divalent
cations mercury (II), lead (II), and cadmium (II). In addition
to identifying protein targets implicated in the toxic effects
caused by these heavy metals, results should show whether
amino acid side chains other than cysteine thiols are important
in the protein-metal binding interaction.
Another project, currently in the planning
stage, involves studying the photochemistry of sunscreen chromophores.
It is currently thought that photo-generated free radicals
cause the DNA damage that leads to sunburn and skin cancer.
Although sunscreens do effectively protect against sunburn,
it is currently not well established whether this translates
into protection against free radical-induced skin cancer.
This project will begin by characterizing the UV spectra of
important sunscreen chromophores in various solvents. Then
we will develop a system to photogenerate free radicals and
assay their concentration in solution. Finally, we will compare
UV absorbance spectra of the sunscreen chromophores with their
ability to inhibit free radical photogeneration in solution
(i.e., their action spectra). In this way we hope to be able
to tease apart the connections, if any, between sunburn, free
radical damage, and skin cancer.
Finally, several other projects are available
in Dr. Silverstein's lab. These include:
(a) studying the degradation of organic pollutants,
using UV light and sonication to degrade PCB's, dioxins, antibiotics,
and other pollutants
(b) studying the degradation of aspartame
(NutraSweet™) by distinguishing between two different
potential hydrolysis pathways, and
(c) probing the transport of ions and electrons
across biological membranes: testing the influence of salt,
temperature, and organic solvents on transport rates.
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